1. Fields of the Invention
The present invention relates to a lens, and more particularly, to a lens for an illumination device and the lens has a multi-focus surface to control the paths and patterns of the light beams.
2. Descriptions of Related Art
The conventional Light Emitting Diode (LED) illumination devices use LEDs as the light source and which has a longer term of life and saves energy. When higher illumination feature is needed, the number of the LEDs are installed, however, the multiple LEDs create multiple light ports on the object to be illuminated and this easily cause fatigue of eyes. A lens is the best way to improve the illumination.
Taiwan Utility Model No. M343112 discloses an LEDs unit connected to the reflection member of the illumination device and a base is connected to the rear side of the reflection member. The base has a circuit board. A cup is connected to the front side of the reflection member and has a hole with which a lens is engaged. The lens is located in front of the LEDs unit. The lens may have different shapes and colors so that the illumination device generates different colors of light beams by using different lenses.
The lens is a convex lens which has different curvatures to guide the light beams. Nevertheless, the distance that the light beams reach, the size that the light beams compass and the paths that the light beams follow cannot be changed. For example, a head light for a bicycle is required to illuminate the road in front of the front wheel, however, the current head light can only provide a ring-like light pattern and half of the light beams are wasted and point upward.
The present invention intends to provide a lens for an illumination device to improve the shortcomings mentioned above.